Herb Gross discusses the evolution of addition algorithms from tally marks through place value and shows that subtraction is an alternative form of addition - all in the context of the all-important adjective noun theme. See www.adjectivenounmath.com
![[help]](/images/question.gif "[help]")
)![[Attribution-Noncommercial-No Derivative Works 3.0]](http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png "[Attribution-Noncommercial-No Derivative Works 3.0]")
![[item image]](http://ia600502.us.archive.org/6/items/ClassicArithmeticAdditionSubtractionOfWholeNumbers/04bModule2AdditionSubtractionOfWholeNumbersTape4-1.gif?cnt=0 "[item image]")
